1. Field of the Invention
The invention relates generally to the field of photography, and in particular to an attitude sensor for determining camera orientation.
2. Description of the Prior Art
Orientation indicating devices to facilitate accurate horizontal positioning of cameras are generally well known. Typically, a spirit level has been used as an attitude sensor for determining orientation of the camera. The spirit level comprises a sealed glass tube filled almost completely with a liquid, leaving a small air bubble. As long as the tube is truly horizontal, the bubble will lie exactly between two reference marks in the middle of the tube to indicate the camera is horizontal. If the tube is inclined left or inclined right along its length because of similar movement of the camera, the bubble will move to the right or the left of the reference marks. However, it is difficult to adjust the tube to locate the bubble between the reference marks and at the same time frame a subject to be photographed.
Commonly assigned U.S. Pat. No. 4,801,793, issued Jan. 31, 1989, discloses an orientation indicating device for visibly indicating in the viewfinder of a camera that the camera is deviated improperly from a normal horizontal position to take a picture. Specifically, the device comprises a pendulum-like contact swingably suspended from a fixed point, but urged to remain vertical by gravity, and a plurality of spaced fixed contacts disposed to make respective electrical connection with the pendulum-like contact as the camera is deviated inclined-left or inclined-right from its normal horizontal position. When the camera is deviated inclined-right or inclined-left, the resulting electrical connection activates orientation indicating means to provide a visible indication of the camera orientation.